Recent Publication in Journal of Clinical Oncology Demonstrating Oncotype DX® Predicts Late Distant Recurrence in Breast Cancer

Findings Confirm that Oncotype DX May Help Identify Breast Cancer Patients with Greatest Potential to Benefit from Extended Hormonal Therapy.

The Journal of Clinical Oncology, the official journal of the American Society of Clinical Oncology (ASCO), published results from a large study confirming the ability of the Oncotype DX® Breast Recurrence Score™, in combination with quantitative estrogen-receptor (ER) expression, to accurately predict after five years of tamoxifen therapy the risk of late distant recurrence up to 15 years in patients with early-stage, hormone receptor-positive breast cancer. These findings suggest that Oncotype DX may help identify which patients are most likely to benefit from extended hormonal treatment with tamoxifen.

"Extending tamoxifen treatment for 10 years has been shown to be associated with better outcomes, but not all patients have the same risk of late distant recurrence - meaning cancer coming back after five years - and it is important to know a patient's risk in order to better understand who will benefit the most from extended hormonal treatment," said Norman Wolmark, M.D., chairman of the National Surgical Adjuvant Breast and Bowel Project (NSABP) Foundation, the organization that carried out the study in conjunction with Genomic Health. "The results of this large study confirm that Oncotype DX helps better define who is at greatest risk of a late distant recurrence and who would likely derive the greatest benefit from extended tamoxifen therapy."

The study analyzed the results of two clinical trials: NSABP B-14 (668 patients) and B-28 (1,065 patients). Patients were followed up on for a median of 13.9 years (B-14) and 11.2 years (B-28). The results reconfirm earlier findings from validation studies of Oncotype DX which demonstrated that Breast Recurrence Score results were strongly associated with distant recurrence up to 15 years for patients with node-positive and node-negative disease.

The results suggest that extending tamoxifen beyond five years may provide greater benefit in patients with high and intermediate Breast Recurrence Score results who also show high ER expression. Conversely, patients with low Breast Recurrence Score results have a much lower risk of late distant recurrence and would be expected to have less benefit from extended tamoxifen beyond five years.